BBC NEWS | Science/Nature | 'Crater' spied under California

BBC NEWS Science/Nature 'Crater' spied under California: "Oil exploration work in California's Central Valley region has uncovered a possible space impact crater.
The 5.5km-wide bowl is buried under shale sediments west of Stockton, in San Joaquin County, and is thought to be between 37 and 49 million years old. "